Lubricating oil



Patented July 23, 1940 mural) STATES P TsNrorrios.'

LUBRICATING OIL Edward J. Martin, East Chicago, and James H. Kirk, Hammond, Ind., assignors to Sinclair Refining Company, New York, N. Y., a cornotation of Maine No Drawing. Application October 2, 1937,

Serial No. 167,017 7 11 Claims.

This invention relates to the treatment of hydrocarbon lubricating oils and, more particularly, to improvements in the method of lowering the pour point of wax-containing hydrocarbon lubrieating oils as well as to the product used for this treatment and the resulting blend of this product with a hydrocarbon lubricating oil or a pour depressor, or both.

Hydrocarbon lubricating oils generally containa substantial quantity of wax and the presence of this wax in the oil is conducive to a high pour point for the oil. That is, oils which contain a substantial quantity of wax do not pour readily at temperatures encountered during winter 15 weather. The temperature at which the oil is too viscous to flow freely depends to a large extent upon the character of the oil, the.amount of wax present in the oil, and the melting point of this wax.

It has been the common procedure to remove from such wax-containing oil a large proportion of the wax in order that the lubricating oil may be used satisfactorily in internal combustion engines, and the like, during cold weather. The removal of the wax entails a substantial expense in the production of lubricating oils having a low pour point. As a result of this 'fact pour depressors have been incorporated in the waxcontaining oil. Sucha pour depressor is a substance which, when incorporated in an oil having a comparatively high pour point, will materially lower the pour point of the oil without necessitating the removal of the wax from the oil. It has been necessary heretofore to incorporate substantial quantities of such pour depressors in wax-containing oils in order to obtain the desired result, and the use of substantial quantities of expensive compounds for this purpose has resulted in a considerable expense in the preparation of these oils for commercial use.

We have found that the use of extraneous wax has the salient advantage ofnot only activatin the effect of the pour depressor in the oil but also of markedly reducing the amount of pour depressor necessary to lower the pour point of the oil to the desired extent. We have discovered that the use of a small proportion of an extraneous wax greatly reduces the amount of pour depressor which would ordinarily be necessary to lower the pour point of a lubricating oil. We have further discovered that the melting point of the extraneous wax should be substantially higher than the melting point of the wax contained in the oil. Thus, while one type of extraneous wax is satisfactory for a lubricating oil containing a wax having a relatively low melting point, this same extraneous wax will not have an appreciable effect upon a lubricating oil containing a wax having a melting point in the neighborhood of that of the extraneous wax.

By the term extraneous 'wax as used herein we mean amorphous as well as crystalline waxes. For example, we may use a crystalline wax having a comparatively low melting point, a comparatively high melting point petrolatum, or a high melting point crystalline wax such as Ozokerite, or the like.

The proportions of extraneous wax which may be used with advantage depends upon the character of the oil to be treated, the melting point of the extraneous wax, and the amount of pour depressor which is used, the latter depending to a large extent upon the desired pour point of the finished product.

We have found that there is generally an optimum proportion of extraneous wax which may be used with particular advantage, this optimum amount varying as noted If too little extraneous wax is used the I above.

pour depressor is not sufficiently activated, while, on the other hand, if too much extraneous wax is used the effect of the pour depressor is nullified. Within a wide range of lubricating oils and a wide range of the amount of pour depressor used we have found that a fraction of one pervcent of an appropriate extraneous wax gives optimum results.

The efiect of varying proportions of the pour dean A. P. I. gravity of 30.6".

'neous wax has a melting point of 153.3" F. and

Table I Percent 0.0% 0.1% 0.2% 0.3% 0.4% Petrolatum depressor depressor depressor depressor depressor 20 F 20 F. 20 F. 20 F. 5 15 3-10 13-10 10 0 13-10 B-10 It will be seen from the foregoing tabulation that 0.1% by weight of this relatively wgh melting point petrolatum produces optimum results up to a concentration of at least 0.4% pour depressor by weight in the oil. It will be noted that with this particular base oil and petrolatum 0.2% by weight of the petrolatum in the oil nullifies the effect of the pour depressor when the latter is used in amounts up to about 0.2% by weight. When larger amounts of the pour depressor are used the point at which the optimum concentration of petrolatum is reached becomes less critical as evidenced by the fact that both 0.1% and 0.2% by weight of petrolatum may be used with advantage when the pour depressor is used in an amount in excess of 0.2% by weight.

The effect of a definite small proportion of an extraneous wax upon the pour point ofdifferent types of oil with varying proportions of a pour depressor is shown in Table II. The base oils used in this table comprise a Mid-Continent neuwith an 011 containing a wax having a melting point considerably below that of the extraneous wax than when used with a more viscous oil containing a wax having a melting point more nearly that of the extraneous wax.

Table III shows the effect of varying quantities of several different waxes when used with varying proportions of a pour depressor. The base oil used in Table III has an A. P. I. gravity of 275, a viscosity of 166.1 seconds Saybolt at 100 F., a viscosity of 43.5 seconds Saybolt at 210 F., and a pour point of 20 F. The petrolatum used in this table has an A. P. I. gravity of 30.6 and a melting point of 153.3 F., while the 163.5" F. melting point wax is that obtained by the deoiling of the above-described petrolatum with a solvent blend comprising benzol, acetone, and toluene and separation of the wax at a temperature of 90 F.

Table III 0.0% pour depressor 0.1% pour depressor 0.2% pour depressor 0.3% pour depressor Percent agdmon 163 5 163 5 163 5 163 5 a en g igg M. P. @331 M. P. igg M. P. ig M. P W8! W81 W32 WBX 30 30 5 20 ---1O B-10 B-lO B-10 25 30 +5 3-10 5 B-10 B-10 B-lO 25 30 20 +5 15 B-IO 5 B-10 20 30 25 20 10 B-lO B-lO Table II Pour point of Pour de- Pour point Type of base on pressor of base oil 221x 63 0. 0% F 0 F -5 F. pout Mid-Cont. 0. 1 -5 15 neutral. 0. 2 -5 B25 0. 3 5 25 0. 4 3-25 0. 5 l6 0.0% 10 F F +l0 F. pour S.A.E.40 0.2 0 5 Mid-Cont. 0. 4 10 5 0. 6 10 10 41.8 -1o 5 From the foregoing table it will be seen that f 0.1% by weight of a crystalline parafline wax having a melting point of 131 F. lowers the pour point of the -5 F. pour Mid-Continent neutral 1 oil more than F. when 0.2% by weight of a is used. It will also be noted that the pour point 1 of the more viscous oil is reduced to a minimum by the use of about 0.6% by weight of the pour depressor while the pour point of the less viscous oil is reduced to a minimum by the use of only I 10.2% by weight of the pour depressor, 0.1% by weight of the parafilne wax being used with both oils. This data is an example of the phenomenon which we have noted, namely, that an extraneous wax having a given melting point is more effective The results of Table III show that the higher melting point wax has a more pronounced elIect in lowering the pour point of an oil containing a pour depressor. Moreover, this tabulation shows, in common with Table I, that with increased proportions of the pour depressor in the oil the optimum concentration of extraneous wax becomes less critical. While 0.1% by weight of petrolatum will lower the pour point of the oil F. when 0.1% by weight of a pour depressor is, used, the same amount of this petrolatum will lower the pour point more than F. when about 0.3% by weight of the pour depressor is used. Thus, it will be seen that the optimum proportion of extraneous wax which may be used with advantage depends to a certain extent upon the amount of pour depressor used and the desired pour point of the finished product.

The extraneouswax may be incorporated in the oil either before or after the pour depressor is added to the oil. On the other hand, the extraneous wax may be incorporated in the pour depressor in the desired proportion so that the resulting blend of pour depressor and extraneous wax will insure the presence in the oil of the optimum concentration of each constituent of the blend. The extraneous wax is, in general, highly soluble in commercial pour depressors such, for example, as those produced by halogenation, polymerization, or condensation of waxy hydrocarbons.

"We do not wish to be limited to the proportions of pour depressor and extraneous wax set forth in the foregoing examples. For example, the amount of pour depressor used may range between about 0.05 to 1.0% by weight, while the extraneous wax may be used in amount between about 0.05 to 0.5% by weight of the oil to be treated. As noted above, the amount of extraneous wax which may be added with advantage varies with the character of the oilxto be treated. Most satisfactory results are to be realized by the use of an extraneous wax having a melting point a -wax-containing hydrocarbon lubricating oil which comprises incorporating in the oil a pour depressor and an extraneous hydrocarbon wax having a melting point substantially higher than the melting point of the wax contained in the oil. 2. The method of lowering the pour point of a wax-containing hydrocarbon lubricating oil which comprises incorporating in the oil a small proportion of a pour depressor and a small proportion of an extraneous hydrocarbon wax having a melting point substantially higher than the melting point of the wax contained in the oil.

3. The method of lowering the pour point of a wax-containing hydrocarbon lubricating oil which comprises incorporating in the oil a small proportion of a blend of a pour depressor and an extraneous hydrocarbon wax having a melting point substantially higher than the melting point of the wax contained in the oil.

4. The method of lowering the pour point of a wax-containing hydrocarbon lubricating oil which comprises incorporating in the oil a fraction of one percent by weight of a pour depressor and a fraction of one percent by weight of an extraneous hydrocarbon wax having a melting 6. The method of lowering the pour point of a wax-containing hydrocarbon lubricating oil.

which comprises incorporating in the oil a fraction of one percent by weight of a blend of a pour depressor and an extraneous hydrocarbon wax having a melting point substantially higher than the melting point of the wax contained in the oil.

'7. The method of lowering the pour point of a wax-containing hydrocarbon lubricating oil which comprises incorporating in the oil between 0.05 and 1.0 percent by weight of a pour depressor and between 0.05 and 0.5 percent by weight of an extraneous hydrocarbon wax having a melting point substantially higher than the melting point of the wax contained in the oil.

8. An improved lubricating oil which comprises a waxcontaining hydrocarbon lubricating "oil containing a small proportion of a pour depressor and a small proportion of an extraneous hydrocarbon wax having a melting point substantially higher than the melting point of the wax contained in the oil.

'9. An improved lubricating oil which comprises a wax-containing hydrocarbon lubricating 011 containing a fraction of one percent by weight of a pour depressor and a fraction of one percent by weight of an extraneous hydrocarbon wax having a melting point substantiallyhigher than the melting point of the wax contained in the oil.

10. An improved lubricating oil which com-r prises a wax-containing hydrecarbon lubricating oil containing between 0.05 and 1.0 percent by weight of a pour depressor and between 0.05 and 0.5 percent by weight of an extraneous hydrocarbon wax having a melting point substantially higher than the melting point of the wax contained in the oil.

11. A pour depressor for use with a wax-containing hydrocarbon lubricating oilwhich comprises a blend of a pour depressor and an extraneous hydrocarbon wax having a melting point substantially higher than the melting point of the wax contained in the oil.

EDWARD J. MARTIN. JAMES H. KIRK. 

